Safety computer systems people

All data generated in a computer system must be available, secure, and safely stored. Unauthorized people cannot have access to data files. It must be impossible to overwrite any data, but all recalculation required must generate a new data and not substitute the previous one. Safety procedures must be available. Data should be backed up periodically following specific SOPs, and backup copies must be iden-... 

This paper could not have been written without the support of a large number of other people. I must thank all the members of EWICS TC7, but particularly Stuart Nunns who in discussion allowed me to reflect on the views of a large UK industrial user of computer systems and the role of standards. Also I must thank the Safety and Reliability Society for the extracts from the 1986 Yearbook. 

It was stated at the symposium that "a computing system may be termed safe if it will not cause death or injury" and that "it may be termed secure if it will not betray any secrets". Whilst some people prefer definitions such as "security is the prevention of fraud or error", one thing that can be agreed is that security concerns the protection of information against some threat, whereas safety concerns the protection of people against some hazard. 

The assessment of the contribution of a product to the fire severity and the resulting hazard to people and property combines appropriate product flammabihty data, descriptions of the building and occupants, and computer software that includes the dynamics and chemistry of fires. This type of assessment offers benefits not available from stand-alone test methods quantitative appraisal of the incremental impact on fire safety of changes in a product appraisal of the use of a given material in a number of products and appraisal of the differing impacts of a product in different buildings and occupancies. One method, HAZARD I (11), has been used to determine that several commonly used fire-retardant—polymer systems reduced the overall fire hazard compared to similar nonfire retarded formulations (12). 

Another important use of computers in safety is monitoring. One can place sensors and data capturing devices to detect the occurrence of unsatisfactory conditions. Sensors feed data to a computer. The system analyzes the information to identify some dangerous condition. It can set off alarms and distribute urgent messages to people who need to know about a condition. There are monitoring systems for certain hazardous gases, for excessive heat or fire, and to detect system failures. 

The purpose of step 1 is to understand where people fit into the system goals and functions. What are some of the assumptions people have toward the system Is the system highly computer controlled Do operators need to read dials and operate valves Focus on the hazards identified in the other system safety analyses. Identify which of those are human induced or can be mitigated by human actions. 

Now these comments may amaze, they may even surprise. They certainly would if the organisations were identified. When one realises that in some cases the people were talking about systems which, on failure, could put life at risk they suddenly become more shocking. Computer-based systems are increasingly used in applications which have become known as safety critical - a phrase well known in the Railway Industry, and sometimes also known as safety-related. ... 

In the fourth paper, the results of a simulation of a flexible manufacturing system are analyzed. Specifically, the optimization of the number of Automated Guided Vehicles (AGVs), machines needed, and job arrival rate is discussed. The fifth paper presents results of a research project on a computer-based safety system for a FMS, especially management logic necessary to avoid various danger situations resulting from the interaction of machines, people, and... 

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